The driver of a vehicle generally controls the course and speed of the vehicle by steering, accelerating and braking the vehicle. Cruise control systems are available that allow a driver to set a desired speed for the vehicle to travel. Normally, if the driver touches the brake pedal, the cruise control system is overridden and control of the vehicle speed is returned to the driver. If a driver depresses the accelerator pedal, the vehicle may remain in cruise control while the vehicle speed is increased while the accelerator remains depressed. After braking, the cruise control system may allow the vehicle to resume a previously set speed. Adaptive cruise control systems have sensors that sense the speed of a vehicle in front of the vehicle that is being operated and adjust the speed setting to assure a sufficient following distance.
Systems are available that assist a driver of a vehicle to parallel park. Parallel parking systems may be activated by positioning the vehicle in a prescribed position relative to an available parking space. Once positioned, the parallel parking system assumes control of the operation of the vehicle until the vehicle is parked in the desired parking space. Parallel parking systems are intended to park a vehicle relative to stationary vehicles that are in a single curb lane and spaced apart a fixed distance.
Autonomous control of vehicles for normal driving on roads is not available in vehicles. A fully autonomous vehicle control system would transfer control of vehicle steering, acceleration and braking to the vehicle control system. Several factors make such systems unacceptable including the difficulty of anticipating upcoming roadway curvature, lane availability, merging lane locations, and the speed and location of surrounding vehicles. In addition, limitations on the ability to sense and quickly process data relating to lane location and the location of surrounding vehicles preclude truly fully autonomous control of vehicles on normal roadways. Roadways are dynamic systems that are constantly changing and it is difficult to program a vehicle for fully autonomous control.